Do I actually need a ctalytic convertor?

Question

My car (X reg Laguna sport) failed it's MOT on emissions today and on investigation it is because my cat is not working - do i actually need a new catalytic convertor, or can my car run without one and still be within the legal limit for emissions somehow..? - i'm just paranoid that as a female the garage is stitching me up as my last car that had a cat problem (a fairly new mondeo) was really obvious that it had a problem - basically because it wouldn't run! I have been running around in this car without the slightest hint that there was anything wrong with the cat..
Any help appreciated!

Answer 1

A Catalytic converter is Mandatory .
That means that without it you are breaking the law.

A modern car is a very complicated piece of machinery and to keep the emissions within specified limits then a catalytic converter is required. If it were possible to run the car without ,and still keep within these stringent limits ,then the manufactures would have removed this expensive equipment long ago.
So yes you need it .
Just an added note ,Its very rare for these converters to fail ,The main reason for failing an emissions test is the oxygen sensor, a faulty injector, or a worn out motor.

Answer 2

If you are looking to pass an emissions test, you definitely need it.

If your catalytic converter is failing, it will cause excessive back pressure in the exhaust and will really hurt the performance and fuel economy.

Modern catalytic converters aren't as restrictive as the earlier ones were, so you will see only a very small performance gain if you remove it. Removing it may even hurt the performance. This is because this will change the exhaust gas temperature, which will be detected by the oxygen sensor. The engine management computer will attempt to compensate, but you may not like the results.

By removing the catalytic converter, you will be putting a lot more pollution into the atmosphere. Not what you want if you are trying to pass an emissions test.

Best to replace it.

If you think the garage is trying to rip you off, bring it to another garage for a second opinion.

Answer 3

I am going to throw a spanner in the works and say that in theory if your cars electronics are working fine and car won't need a cat to pass emissions at MOT. The catalyst is installed to remove NOX and this is carried out in the catalyst when it is at the correct working temperature. You may have noticed an eggy smell as the car warmed up? This is the cat trying to burn of NOX gases as it warms up. There are 3 types of precious metals inside a cat, rhodium, palladium and platinum and these are covered in a special coating called a wash coat, the wash coat absorbs these NOX gases and turns some of the gases to O2, this is the water that drips from your exhaust.
There are inline sensors which detect how much air/fuel mixture is required for the engine to run, I would suggest a fuel additive that helps clean fuel injectors and can also help clean the combustion chamber and helps the lambda sensor see a cleaner emission and then can fuel more efficiently. End result, cleaner emissions. Lastly, with todays EOBD systems in cars, especially Renault, If there had have been a fault, I would have expected your MIL to have come on or be on alerting you of a potential fault.
Hope this helps.
Cheers

Answer 4

Sure it can run without one just fine, but it will never pass an emissions test. This unfortunately is a sad fact but true. It's supposed to be an issue with pollution control issue in some states, It was a regulation here in michigan for a few years, but the public lobbied and complained so hard it was quickly halted, because it also meant that any car built without the catalytic converter or before there were converters could not legally be driven since they could not pass the emissions test.

Answer 5

Federal laws make it mandatory that any auto that came equipped with a cat. converter must have one in working order to pass the emissions tests. As to how the cat converter fails, one of two things can happen. 1. The converter may build up with carbon or other combustion by-products and restrict the exhaust to the point the engine suffers lack of drivabilty. 2. The converter may just burn out, all the catalyst is used and is blown out with the exhaust, in which case the drivability of the car is not compromised (this sounds like what may have happened in your case as you had no driving issues) Sorry, but to have the car pass and be legal you must have the new converter. Talk to friends & Family to choose the best place to get the work done, at least if someone you know has had work done at a specific place you can rest a little easier.

Answer 6

Legally if the car came with you are required to have one even if a previous owner removed it.

Mechanically if you do not have an oxygen sensor behind the catalytic converter you don't need one for the vehicle to run correctly. However you will have a hard time passing any emission test.

Answer 7

The cat is not an aid to good running so a car will run about the same without it ,But the law is that all cars of that type have to have low emissions so you have to obey to get your mot . a cat works by heating a set of fine gauze meshes they glow red hot from the hot exhaust gases as the gases pass through them the toxins are burnt off lowering the toxic emissions

Answer 8

Your car will run fine without one, but it will never pass an E-test. In fact, they won't even let you take an e-test until you get it replaced. Cats aren't that expensive (usually $50 -$150 CAD), and shouldn't be more than an hour labour at the shop. If you're the least bit mechanically inclined, you can replace it yourself. ( if you don't weld, exhaust clamps and sealant will work to attach it)

The cat is simply to control pollutants. It contains a precious metal (usually platinum) that reacts with certain pollutants to render them less harmful to the environment. There are other types that work differently as well, but that is the most common one..

Answer 9

How can it not be working? i just dont understand this at all,did you take a short journey to the mot station?if so it could be that it did not get hot enough to work as it should,try a long run round 10 miles to make sure it is hot enough and take you car somewhere else for its mot,if you have to join a queue leave engine running as long as possible,if it fails again then it is new cat time

Answer 10

you must have a cat or you will never get through the m.o.t. emissions test. You mondeo would not run because the cat had broken up and sealed up the exhaust preventing Any gasses from escaping(a common problem)